The Piezo1 cation channel mediates uterine artery shear stress mechanotransduction and vasodilation during rat pregnancy

During mammalian pregnancy, the uterine circulation must undergo substantial vasodilation and growth to maintain sufficient uteroplacental perfusion. Although we and others have shown that nitric oxide (NO) is a key mediator of these processes, the mechanisms that augment uterine artery NO signaling during gestation have not been identified. We hypothesized that Piezo1, a recently discovered cation channel, may be involved in the process of shear stress mechanotransduction, as other studies have shown that it is both mechanosensitive and linked to NO production. Surprisingly, there are no studies on Piezo1 in the uterine circulation. Our aims in the present study were to determine whether this novel channel is 1) present in uterine arteries, 2) regulated by gestation, 3) functionally relevant (able to elicit rises in intracellular Ca2+ concentration and vasodilation), and 4) linked to NO. Immunohistochemistry confirmed that Piezo1 is present in uterine arteries, primarily but not exclusively in endothelial cells. Western blot analysis showed that its protein expression was elevated during gestation. In pressurized main uterine arteries, pharmacological activation of Piezo1 by Yoda1 produced near maximal vasodilation and was associated with significant increases in intracellular Ca2+ concentration in endothelial cell sheets. Shear stress induced by intraluminal flow produced reversible vasodilations that were inhibited >50% by GsMTx-4, a Piezo1 inhibitor, and by Nω-nitro-l-arginine methyl ester/ Nω-nitro-l-arginine, inhibitors of NO synthase. These findings are the first to implicate a functional role for Piezo1 in the uterine circulation as a mechanosensor of endothelial shear stress. Moreover, our data demonstrate that Piezo1 activation leads to vasodilation via NO and indicate that its molecular expression is upregulated during pregnancy. NEW & NOTEWORTHY This is the first study to highlight Piezo1 in the uterine circulation. As a potentially important endothelial mechanosensor of shear stress, Piezo1 may be linked to mechanisms that support increased uteroplacental perfusion during pregnancy. Listen to this article’s corresponding podcast at https://ajpheart.podbean.com/e/piezo1-mechanotransduction-in-the-uterine-circulation/ .

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Reduced NO signaling during pregnancy attenuates outward uterine artery remodeling by altering MMP expression and collagen and elastin deposition

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00519.2011 ◽

2011 ◽

Vol 301 (4) ◽

pp. H1266-H1275 ◽

Cited By ~ 18

Author(s):

Sarah A. Hale ◽

Lindsey Weger ◽

Maurizio Mandala ◽

George Osol

Keyword(s):

Nitric Oxide ◽

Uterine Artery ◽

Vascular Wall ◽

Female Rats ◽

Uterine Arteries ◽

Tissue Inhibitors Of Metalloproteinase ◽

No Signaling ◽

Underlying Mechanisms ◽

Uterine Circulation ◽

Endothelial Nitric Oxide

Recent findings indicate that endothelial nitric oxide (NO) plays a key role in uterine artery outward circumferential remodeling during pregnancy. Although the underlying mechanisms are not known, they likely involve matrix metalloproteinases (MMPs). The goal of this study was to examine the linkage among NO inhibition, expansive remodeling, and MMP expression within the uterine vascular wall. Adult female rats were treated with NG-nitro-l-arginine methyl ester [l-NAME (LPLN)] beginning on day 10 of pregnancy and until death at day 20 and compared with age-matched controls [late pregnant (LP)]. Mean arterial pressure of LPLN rats was significantly higher than controls. LPLN fetal and placental weights were significantly reduced compared with controls. Main uterine arteries (mUA) were collected to determine dimensional properties (lumen area and wall thickness), collagen and elastin content, and levels of endothelial nitric oxide synthase (eNOS) and MMP expression. Circumferential remodeling was attenuated, as evidenced by significantly smaller lumen diameters. eNOS RNA and protein were significantly (>90%) decreased in the LPLN mUA compared with LP. Collagen and elastin contents were significantly increased in LPLN rats by ∼10 and 25%, respectively, compared with LP ( P < 0.05). Both MMP-2 and tissue inhibitors of metalloproteinase-2 as assessed by immunofluorescence were lower in the endothelium (reduction of 60%) and adventitia (reduction of 50%) of LPLN compared with LP mUA. Membrane bound MMP-1 (MT1-MMP) as assessed by immunoblot was significantly decreased in LPLN. These data suggest a novel contribution of MMPs to gestational uterine vascular remodeling and substantiate the linkage between NO signaling and gestational remodeling of the uterine circulation via altered MMP, TIMP-2, and MT1-MMP expression and activity.

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Pregnancy enhances endothelium-dependent relaxation of ovine uterine artery: role of NO and intracellular Ca2+

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2001.281.1.h183 ◽

2001 ◽

Vol 281 (1) ◽

pp. H183-H190 ◽

Cited By ~ 25

Author(s):

Daliao Xiao ◽

William J. Pearce ◽

Lubo Zhang

Keyword(s):

Smooth Muscle ◽

Uterine Artery ◽

No Production ◽

Ionophore A23187 ◽

Uterine Arteries ◽

Pregnant Sheep ◽

No Release ◽

Intracellular Ca ◽

Near Term ◽

Endothelium Dependent Relaxation

The present study tested the hypothesis that the pregnancy-associated increase in endothelium-dependent relaxation of the uterine artery was mediated primarily by an increase in nitric oxide (NO) release, resulting in a reduction in smooth muscle intracellular Ca2+ concentration ([Ca2+]i). Uterine arteries obtained from nonpregnant and near-term (140 days gestation) pregnant sheep were used. The Ca2+ ionophore A23187 induced endothelium-dependent relaxations in both nonpregnant and pregnant uterine arteries, with an increased relaxation in the pregnant tissue. In contrast, endothelium-independent relaxations induced by sodium nitroprusside were the same in nonpregnant and pregnant arteries. In addition, removal of the endothelium significantly increased noradrenaline-induced contractions in pregnant, but not nonpregnant, uterine arteries. In accordance, pregnancy increased both basal and A23187 -stimulated NO releases in the uterine artery. Simultaneous measurement of tension and [Ca2+]i in the smooth muscle demonstrated a linear correlation with the slope of unity between A23187 -induced relaxation and the reduction of [Ca2+]i in both nonpregnant and pregnant uterine arteries. The A23187 -induced reduction of [Ca2+]i was significantly enhanced in pregnant, compared with nonpregnant, uterine arteries. The results indicate that pregnancy increases NO release, which, through decreasing [Ca2+]i in the smooth muscle, accounts for the increased endothelium-dependent relaxation of the uterine artery. Signal transduction pathways distal to NO production are not changed by pregnancy.

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Effects of chronic hypoxia on Ca2+ mobilization and Ca2+ sensitivity of myofilaments in uterine arteries

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1998.274.1.h132 ◽

1998 ◽

Vol 274 (1) ◽

pp. H132-H138 ◽

Cited By ~ 21

Author(s):

Lubo Zhang ◽

Daliao Xiao

Keyword(s):

Smooth Muscle ◽

Fluorescence Intensity ◽

Uterine Artery ◽

Chronic Hypoxia ◽

Effective Concentration ◽

Uterine Arteries ◽

Agonist Stimulation ◽

Pregnant Sheep ◽

Half Maximal Effective Concentration ◽

Intracellular Ca

The effect of chronic hypoxia on free intracellular Ca2+ concentration ([Ca2+]i) and Ca2+ sensitivity of myofilaments during agonist stimulation was examined in uterine arteries obtained from normoxic and chronically hypoxic pregnant sheep maintained at high altitude (3,820 m) for ∼110 days. Smooth muscle [Ca2+]iwas measured simultaneously with muscle contraction in the same intact tissue. Whereas both KCl and 5-HT increased [Ca2+]iand tension simultaneously in the uterine artery, 5-HT produced significantly greater contractile tension (in g) than KCl at a given amount of [Ca2+]ias indicated by the ratio of fura 2 fluorescence intensity induced by excitation at 340 nm to that induced at 380 nm (29.8 ± 6.9 vs. 16.9 ± 4.0, P < 0.05). Chronic hypoxia did not change KCl-induced contractions, nor did it affect KCl-mediated increases in [Ca2+]i. In contrast, chronic hypoxia significantly inhibited 5-HT-induced contractions and decreased the 5-HT-stimulated increase in [Ca2+]i(pD2 7.46 ± 0.18 → 6.86 ± 0.11, P < 0.05, where pD2 is −log half-maximal effective concentration) in uterine arteries. In addition, the slope (g tension/nM [Ca2+]i) of the 5-HT-mediated [Ca2+]i-tension relationship was significantly decreased in chronically hypoxic arteries (0.024 ± 0.002 → 0.013 ± 0.001, P < 0.01). The results suggest that chronic hypoxia suppresses agonist-mediated Ca2+ homeostasis in uterine arteries by inhibiting Ca2+mobilization and the agonist-enhanced Ca2+ sensitivity of myofilaments.

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Pregnancy attenuates uterine artery pressure-dependent vascular tone: role of PKC/ERK pathway

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01238.2005 ◽

2006 ◽

Vol 290 (6) ◽

pp. H2337-H2343 ◽

Cited By ~ 35

Author(s):

DaLiao Xiao ◽

John N. Buchholz ◽

Lubo Zhang

Keyword(s):

Uterine Artery ◽

Vascular Tone ◽

Mek Inhibitor ◽

Intraluminal Pressure ◽

Myogenic Tone ◽

Uterine Arteries ◽

Intracellular Ca ◽

Myogenic Responses ◽

The Difference ◽

Near Term

The mechanisms of adaptation of uterine artery vascular tone to pregnancy are not fully understood. The present study tested the hypothesis that pregnancy decreases the PKC-mediated Ca2+ sensitivity of the contractile process and attenuates myogenic tone in resistance-sized uterine arteries. In pressurized uterine arteries from nonpregnant (NPUA) and near-term pregnant (PUA) sheep, we measured, simultaneously in the same tissue, vascular diameter and vessel wall intracellular Ca2+ concentration ([Ca2+]i) as a function of intraluminal pressure. In both NPUA and PUA, membrane depolarization with KCl caused a rapid increase in [Ca2+]i and a decrease in diameter. A pressure increase from 20 to 100 mmHg resulted in a transient increase in diameter that was associated with an increase in [Ca2+]i, followed by myogenic contractions in the absence of further changes in [Ca2+]i. In addition, activation of PKC by phorbol 12,13-dibutyrate induced a decrease in diameter in the absence of changes in [Ca2+]i. Pressure-dependent myogenic responses were significantly decreased in PUA compared with NPUA. However, pressure-induced increases in [Ca2+]i were not significantly different between PUA and NPUA. The ratio of changes in diameter to changes in [Ca2+]i was significantly greater for pressure-induced contraction of NPUA than that of PUA. Inhibition of PKC by calphostin C significantly attenuated the pressure-induced vascular tone and eliminated the difference of myogenic responses between NPUA and PUA. In contrast, the MAPKK (MEK) inhibitor PD-098059 had no effect on NPUA but significantly enhanced myogenic responses of PUA. In the presence of PD-098059, there was no difference in pressure-induced myogenic responses between NPUA and PUA. The results suggest that pregnancy downregulates pressure-dependent myogenic tone of the uterine artery, which is partly due to increased MEK/ERK activity and decreased PKC signal pathway leading to a decrease in Ca2+ sensitivity of myogenic mechanism in the uterine artery during pregnancy.

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Structural changes in uterine tissues after uterine artery embolization in patients with leiomyoma complicated by uterine bleeding

GYNECOLOGY ◽

10.26442/2079-5696_20.1.78-82 ◽

2018 ◽

Vol 20 (1) ◽

pp. 78-82

Author(s):

G P Titova ◽

M M Damirov ◽

L S Kokov ◽

O N Oleynikova ◽

G E Belozerov

Keyword(s):

Uterine Artery Embolization ◽

Uterine Artery ◽

Structural Changes ◽

Morphological Changes ◽

Uterine Bleeding ◽

Small Scale ◽

Artery Embolization ◽

Vessel Occlusion ◽

Uterine Arteries ◽

Uterine Tumors

Uterine leiomyoma (UL) is often complicated by the development of uterine bleeding. In urgent gynecology for the implementation of endovascular hemostasis, uterine artery embolization (UAE) is used. Performing UAE allows to stop and/or significantly reduce the intensity of bleeding and prepare a patient for surgical intervention. At the same time, the morphological changes that occur in uterine tissues in operated UL patients after performing the UAE are not studied. The aim was to study the peculiarities of pathomorphological changes in uterine tumors and tissues in operated UL patients complicated by uterine bleeding after performing UAE. Material and methods. The results of morphological changes appearing in tumors and tissues of the uterus in 39 operated UL patients, who were used for stopping uterine bleeding, were analyzed. Results. After applying different types of embolizing agents in macroscopic study of the uterus, signs of ischemia of its tissues were revealed, and the most pronounced disorders were detected in the UL nodes. Morphologically it was established that UAE microemboli resulted in vessel occlusion with increasing thrombosis in their distal sections. UAE was not accompanied by occlusal occlusion of the arteries and resulted in small-scale necrosis of the tumor with complete regeneration of the endometrium. Conclusions. The results of the morphological study showed that after the UAE was performed, the myomatous nodes underwent dystrophic, necrobiotic and necrotic changes. Depending on the nature of occlusion of the uterine arteries, various variants of necrosis (scale and completeness of the process) developed in the tumor tissue, which was aseptic in nature.

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Laminar shear stress upregulates endothelial Ca2+-activated K+ channels KCa2.3 and KCa3.1 via a Ca2+/calmodulin-dependent protein kinase kinase/Akt/p300 cascade

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00642.2012 ◽

2013 ◽

Vol 305 (4) ◽

pp. H484-H493 ◽

Cited By ~ 18

Author(s):

Jun Takai ◽

Alexandra Santu ◽

Haifeng Zheng ◽

Sang Don Koh ◽

Masanori Ohta ◽

...

Keyword(s):

Shear Stress ◽

Transcriptional Activation ◽

Static Condition ◽

Fold Increase ◽

Laminar Shear Stress ◽

Human Coronary Artery ◽

Intracellular Ca ◽

Kinase Cascade ◽

Dependent Protein ◽

Laminar Shear

In endothelial cells (ECs), Ca2+-activated K+ channels KCa2.3 and KCa3.1 play a crucial role in the regulation of arterial tone via producing NO and endothelium-derived hyperpolarizing factors. Since a rise in intracellular Ca2+ levels and activation of p300 histone acetyltransferase are early EC responses to laminar shear stress (LS) for the transcriptional activation of genes, we examined the role of Ca2+/calmodulin-dependent kinase kinase (CaMKK), the most upstream element of a Ca2+/calmodulin-kinase cascade, and p300 in LS-dependent regulation of KCa2.3 and KCa3.1 in ECs. Exposure to LS (15 dyn/cm2) for 24 h markedly increased KCa2.3 and KCa3.1 mRNA expression in cultured human coronary artery ECs (3.2 ± 0.4 and 45 ± 10 fold increase, respectively; P < 0.05 vs. static condition; n = 8–30), whereas oscillatory shear (OS; ± 5 dyn/cm2 × 1 Hz) moderately increased KCa3.1 but did not affect KCa2.3. Expression of KCa2.1 and KCa2.2 was suppressed under both LS and OS conditions, whereas KCa1.1 was slightly elevated in LS and unchanged in OS. Inhibition of CaMKK attenuated LS-induced increases in the expression and channel activity of KCa2.3 and KCa3.1, and in phosphorylation of Akt (Ser473) and p300 (Ser1834). Inhibition of Akt abolished the upregulation of these channels by diminishing p300 phosphorylation. Consistently, disruption of the interaction of p300 with transcription factors eliminated the induction of these channels. Thus a CaMKK/Akt/p300 cascade plays an important role in LS-dependent induction of KCa2.3 and KCa3.1 expression, thereby regulating EC function and adaptation to hemodynamic changes.

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Effects of Fluid Shear Stress on eNOS mRNA Expression and NO Production in Human Endothelial Progenitor Cells

Cardiology ◽

10.1159/000092636 ◽

2006 ◽

Vol 106 (2) ◽

pp. 82-88 ◽

Cited By ~ 42

Author(s):

Jun Tao ◽

Zhen Yang ◽

Jie-Mei Wang ◽

Chang Tu ◽

Shi-Rong Pan

Keyword(s):

Shear Stress ◽

Mrna Expression ◽

Progenitor Cells ◽

Endothelial Progenitor Cells ◽

Fluid Shear Stress ◽

No Production ◽

Fluid Shear ◽

Endothelial Progenitor ◽

Enos Mrna

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Endothelial Shear Stress

Circulation Cardiovascular Imaging ◽

10.1161/circimaging.109.916304 ◽

2010 ◽

Vol 3 (5) ◽

pp. 578-585 ◽

Cited By ~ 23

Author(s):

Raphaël Duivenvoorden ◽

Ed VanBavel ◽

Eric de Groot ◽

Erik S.G. Stroes ◽

Jonathan A. Disselhorst ◽

...

Keyword(s):

Shear Stress ◽

Endothelial Shear Stress

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Hypothermia-induced cardioprotection using extended ischemia and early reperfusion cooling

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01312.2005 ◽

2007 ◽

Vol 292 (4) ◽

pp. H1995-H2003 ◽

Cited By ~ 54

Author(s):

Zuo-Hui Shao ◽

Wei-Tien Chang ◽

Kim Chai Chan ◽

Kim R. Wojcik ◽

Chin-Wang Hsu ◽

...

Keyword(s):

Nitric Oxide ◽

Protein Kinase ◽

Therapeutic Hypothermia ◽

Optimal Timing ◽

No Production ◽

Early Reperfusion ◽

No Signaling ◽

Nos Inhibitor ◽

Oxide Synthase ◽

Pkc Activation

Optimal timing of therapeutic hypothermia for cardiac ischemia is unknown. Our prior work suggests that ischemia with rapid reperfusion (I/R) in cardiomyocytes can be more damaging than prolonged ischemia alone. Also, these cardiomyocytes demonstrate protein kinase C (PKC) activation and nitric oxide (NO) signaling that confer protection against I/R injury. Thus we hypothesized that hypothermia will protect most using extended ischemia and early reperfusion cooling and is mediated via PKC and NO synthase (NOS). Chick cardiomyocytes were exposed to an established model of 1-h ischemia/3-h reperfusion, and the same field of initially contracting cells was monitored for viability and NO generation. Normothermic I/R resulted in 49.7 ± 3.4% cell death. Hypothermia induction to 25°C was most protective (14.3 ± 0.6% death, P < 0.001 vs. I/R control) when instituted during extended ischemia and early reperfusion, compared with induction after reperfusion (22.4 ± 2.9% death). Protection was completely lost if onset of cooling was delayed by 15 min of reperfusion (45.0 ± 8.2% death). Extended ischemia/early reperfusion cooling was associated with increased and sustained NO generation at reperfusion and decreased caspase-3 activation. The NOS inhibitor Nω-nitro-l-arginine methyl ester (200 μM) reversed these changes and abrogated hypothermia protection. In addition, the PKCε inhibitor myr-PKCε v1-2 (5 μM) also reversed NO production and hypothermia protection. In conclusion, therapeutic hypothermia initiated during extended ischemia/early reperfusion optimally protects cardiomyocytes from I/R injury. Such protection appears to be mediated by increased NO generation via activation of protein kinase Cε; nitric oxide synthase.

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